Remove netcdf4 from compile

Strange error on Hopper when compiling:

m2c    -o /usr/common/usg/netcdf/cray/4.1.3/gnu/46/include/netcdf -e /usr/common/usg/netcdf/cray/4.1.3/gnu/46/include/netcdf /usr/common/usg/netcdf/cray/4.1.3/gnu/46/include/netcdf.mod
gmake: m2c: Command not found

makefile is identical to netcdf implementation, apart from
source code name change.